What does the “Global pivot” in User preferences do?
In the 3D viewport, we can choose between several pivot points: bounding box, 3d cursor, median point, individual origins...

In 2.7x, when you have more than one 3D view this option makes each 3D view use the same pivot option, when it is off you can change each viewport to use a different pivot point.

In 2.80 this option appears to have been removed, the pivot point is now always the same in each viewport.